Refrigeration system



Oct. 7, 1969 F, LOFGREEN ETAL 3,470,707

REFRIGERATION SYSTEM Filed Feb. 12, 1968 Her/9y 17. Co 990 urn final rawIla/green United States Patent 3,470,707 REFRIGERATION SYSTEM Andrew F.Lofgreen and Harley L. Coggburn, both Andrew Lofgreen, P.O. Box 948, BigBear Lake, Calif. 92315 Filed Feb. 12, 1968, Ser. No. 704,619 Int. Cl.F25b 41/00, 27/02, 43/00 US. Cl. 62-196 7 Claims ABSTRACT OF THEDISCLOSURE A refrigeration system including, an elongate evaporator withinlet and outlet ends, a liquid vapor phase separator connected with theevaporator, a liquid pump connected with and draining liquid from theseparator, a delivery line from the liquid pump to a generator, aventuri in the delivery line to accelerate the rate of flow ofrefrigerant therethrough, a vapor pump connected with and extractingvapor from the separator and connected with the delivery line downstreamof the venturi and injecting vapor into said line, an elongate condenserwith inlet and outlet ends, a flow line from the generator to the inletend of the condenser, a receiver connected with the outlet end of thecondenser and flow control and expansion means between the receiver andthe inlet end of the evaporator to control the rate of flow of highpressure liquid refrigerant from the receiver and into the evaporator.

In general, thermally operated or absorption type refrigeration systemshave been less than moderately successful because of an inherentlyrelatively low coeflicient of performance. A major shortcoming ofabsorption type systems resides in the large quantities of rejected heatand the requirements of bulky accessory equipment, such as condensers,cooling towers and the like.

Further, compression type refrigeration systems are normally such thatthey must be carefully and accurately installed and set, to the end thatthey are, in addition to being ineflicient, unsuitable for use inautomobiles or other like installations where minimal space is availableand where the system is subject to being moved about and its positionvaried.

In general, compression type refrigeration systems are more versatilethan absorption type systems and are such that they can be made smalland compact and are unaffected by movement or change in position.Accordingly, this type of system is suitable for and finds wide use inautomotive air conditioning systems or units. The principal shortcomingin compression type systems resides in the fact that a large, heavy andineflicient compressor must be provided.

In the case of the ordinary automotive air conditioning unit, utilizingthe compression system, a compressor is driven by the automobile engine.Such compressors normally require from ten to fifteen horsepower, fromthe engine, to effect operation of the refrigeration system.

It is an object of our invention to provide a refrigeration system ofthe character referred to suitable for use in automotive airconditioning units and the like, which utilizes heat from the automobileengine exhaust system to operate a heat absorption phase of the systemand which includes a fractional horsepower liquid pump and a fractionalhorsepower vapor pump to operate a compressor phase of the system, theaggregate power of the pumps being less than one horsepower and theoutput of the system being equal to the output of compression typesystems requiring from ten to fifteen horsepower.

It is an object of our invention to provide a system of the characterreferred to including a boiler or generator related to the exhaustsystem of an internal combustion ice engine which serves to increase thetemperature and thus the pressure of the refrigerant (Freon #12) and toassist in maintaining the refrigerant in motion.

It is another object of our invention to provide a liquid vapor phaseseparator type accumulator at the discharge end of an evaporator, apositive displacement liquid pump to draw liquid refrigerant from saidaccumulator and a vapor pump to draw gaseous refrigerant and refrigerantvapor from said accumulator whereby the volume of refrigerant containedin said accumulator is maintained sufficiently low to receive the flowof refrigerant from the evaporator at all times.

It is yet another object of our invention to provide a system of thecharacter referred to wherein the liquid pump moves and dischargesliquid refrigerant from the low pressure to the high pressure side ofthe system and through the generator. Accordingly, it is an object ofthis invention to provide a system wherein the movement of liquidrefrigerant is employed to move and ciruulate gaseous refrigerantthrough the system.

Another object of the present invention is to provide a system of thecharacter referred to wherein gaseous or vaporous refrigerant dischargedby the vapor pump is combined with the refrigerant discharged by theliquid pump, downstream of the generator, whereby the gaseous andvaporous refrigerant, being at. a higher temperature and resultinghigher pressure, induces vaporization and expansion of the liquidrefrigerant and resulting increased velocity or rate of flow of thepumped refrigerant flowing into and through the generator.

Yet another object of our invention is to provide a system of thecharacter referred to including a flow metering means at the dischargeside of the liquid pump and downstream of the connection with thedischarge of the vapor pump which means maintains sufliicient headpressure at the discharge side of the liquid pump to maintain therefrigerant in a liquid state and which creates a pressure drop at itsdownstream side whereby the liquid refrigerant expends sufliciently toaccelerate its rate of flow and cools sufiiciently to create atemperature and resulting pressure drop so that the necessary pressuredifferential between the discharge of the vacuum pump and the linepressure is sufiicient to assure injection of the discharge of thevacuum pump into the line.

It is to be noted that the pumps and the generator of our invention donot perform the full corresponding functions of pumps and generators intrue compression and absorption type systems, but serve, primarily, toestablish and maintain a high pressure, high velocity flow ofrefrigerant at the downstream end of the high pressure side of thesystem, which high pressure, high velocity flow creates the necessaryand desired operating pressure and temperature differential below thehigh and low pressure sides of the system.

The foregoing and other objects and features of our invention will befully understood] and will become apparent from the following detaileddescription of a typical preferred form and application of ourinvention, throughout which description reference is made to theaccompanying diagrammatic drawing of our system.

The apparatus and system that we provide includes a plurality ofinterconnected and related refrigerant handling and conductingcomponents, parts and means, and defines a circuit having high and lowpressure sides.

The high pressure side of the circuit includes, generally refrigeranttransporting means T, a condenser C, a receiver R, and flow controlmeans F.

The lower pressure side of the circuit includes an evaporator E and anaccumulator A.

The evaporator E is shown as a direct expansion type evaporator coilhaving an inlet end 10 connected with the flow control means of the highpressure side of the system and into which liquidrefrigerant isintroduced, to flow therethrough, expand partially or totally into vaporand/ or gas, and to thereby absorb heat from the ambient atmosphere. Theevaporator E has an outlet or discharge end 11 which is connected withthe accumulator A.

The accumulator A is a liquid vapor phase type accumulator and consistsof a closed tank or vessel 12 with an inlet opening or fitting 13 withwhich the outlet 11 of the evaporator is connected, as by a line 14, aliquid outlet opening or fitting 15 at its lowermost or bottom side anda vapor-gas opening or fitting 16 at its uppermost or top side.

The accumulator A is adapted to receive the refrigerant discharged fromthe evaporator.

The refrigerant transporting means T of the high pressure side of thesystem is intended to perform the function of a compressor in acompression type refrigeration system or a generator (boiler) in a heatabsorption refrigeration system and to that extent may be termed apumping means. The means T may also and properly be defined as a flowaugmenting means, the function of which is to accelerate the flow ofrefrigerant in the high pressure side of the system to effect anoperative pressure differential between the high and low pressure sidesof the system.

The means T includes a liquid pump L, a vapor pump V, flow acceleratingmeans M related to the liquid pump L, vapor injecting means I and agenerator (boiler) G.

The liquid pump L can be of any type or design of pump suitable formoving liquids and is preferably a positive displacement gear type pump.The pump L can be driven by any suitable prime mover and, in practice,is driven by an electiric motor E.

The gas or vapor pump V can be of any type or design of pump suitablefor moving gases and vapors, such as a vane type or diaphram type ofpump. The pump V can be driven by any suitable prime mover and, inpractice, is driven by an electric motor E.

The inlet side of the pump L is connected with the liquid outlet fitting15 of the accumulator A by a suction line 17 and the inlet side of thepump V is connected with the gas outlet fitting 16 of the accumulator ofa suction line 18.

Connected with the discharge side of the liquid pump L and extending toand connected with the genarator G is a delivery line 20.

The flow accelerating means M is engaged in the line 20 and is adaptedto accelerate the rate of flow of refrigerant in the line and issuingfrom the pump L.

The means M is shown as a simple venturi 21 arranged in the line 20.

The function of the means M or venturi is to accelerate the rate of flowof liquid refrigerant in the line 20 and at the same time create apressure drop which causes a portion of the accelerated liquid tovaporize whereby the accelerated rate of flow does not diminish ordiminish rapidly or noticeably downstream of the venturi.

It is to be noted that the means M or venturi 21 creates a back pressureor head in the line 20 upstream of the venturi, which head inhibitspremature vaporization of the refrigerant in the line.

Further, the noted expansion of the accelerated refrigerant effectivelycools the refrigerant and lowers its corresponding pressure.

The vapor injecting means I involves a lateral tapfitting 22, such as aT-fitting, in the line 20 downstream of the means M and connected with avapor line 23 extending from and connected with the discharge side ofthe vapor pump V.

The temperature and resulting or corresponding pressure of the vapordelivered by the pump and flowing through the vapor line 23 is greaterthan the temperature and pressure of the refrigerant in the line 20downstream of the venturi. Accordingly, the vapor is injected into theaccelerated and rapidly moving flow of refrigerant in the line 20. Theinjected vapor adds to or increases the volume of refrigerant flowingthrough the line 20 and increases the temperature and pressure of therefrigerant, inducing further vaporization of liquid refrigerant. Thisresults in further acceleration of the refrigerant in the line 20.

The foregoing explanation of the function and effect of the T-fitting ofthe means M has been determined by observation of the system when inoperation and while believed to be substantially correct, may betechnically inaccurate in certain respects.

The generator G can be any suitable generator or boiler construction andcan be related to any suitable heat source. In the case illustrated, andin the preferred carrying out of the invention, the generator is thatform of generator shown in Patent No. 2,659,214, issued to Harley L.Coggburn on Nov. 17, 1953, and is adapted to be related to the exhaustsystem S of an automobile engine.

The generator G illustrated includes a boiler portion 30 having inletand outlet openings 31 and 32 and a fire box or heater portion 3 3which, in the instant case, is provided with gas inlet and outletopenings and is arranged in an exhaust gas bypass pipe 34 related to thesystem S.

The generator G is essentially a heat exchanger and is provided to heatand vaporize the refrigerant by means of heat from the engine exhaustgases flowing through the system S.

The inlet opening 31 of the generator G is connected with the downstreamend of the line 20 and the outlet opening 32 is connected with thecondenser C by a conductor line 33.

The rapidly moving refrigerant flowing through the line 20 is deliveredinto the generator and is heated and further vaporized therein and isdischarged therefrom through the line 33 at high velocity, hightemperature and resulting high pressure, but in a rare state (minimalmass) wherein its heat carrying capacity, by volume, is minimal.

The condenser C is a conventional coil type heat exchanger ahd has inletand outlet fittings or openings 35 and 36 at the opposite ends of thecoil. The line 33 conneots with the inlet fitting 35 and the outletfitting 36 is connected with the receiver R.

The receiver R is a simple tank or vessel to receive and collect liquidrefrigerant flowing from the condenser and has an inlet opening 37suitably connected with the outlet end of the condenser and an outletopening 38.

The rare, heated refrigerant, at high pressure flowing into thecondenser, is rapidly cooled and condenses therein and is dischargedtherefrom and into the receiver R in a liquid state and at highpressure.

The flow control means F is that means provided to conduct the cool,high pressure liquid refrigerant collected by the receiver from thereceiver R to the evaporator E. The means F can vary widely in formwithout departing from the spirit of this invention.

In the case illustrated, the means F includes an expansion valve 40connected with the inlet end of the evaporator E and a liquid line 41extending from the expansion valve 40 to the receiver R. The line 41extends through the opening 38 in the receiver R and opens Within thereceiver R at the bottom thereof and within the liquid.

In addition to the foregoing, the means F is shown as including a flowcontrol or flow metering device, such as a flow bean, or, asillustrated, a metering valve 42 in the line 41 to limit and/ or controlthe volume of refrigerant flowing from the receiver R through the line41 and into, through and thence from the expansion valve 40 and into theevaporator E.

In practice, the expansion valve 40, line 41 and valve 42 could bereplaced with a capillary tube without departing from the spirit of thisinvention, since such a substitution would constitute the use of awell-known mechanical equivalent.

The refrigerant issuing from the expansion valve 40 flows into andthrough the low pressure side of our system to complete therefrigeration cycle.

In practice, and in a system as provided by this invention, for use inan automobile air conditioning unit and using Freon #12 as therefrigerant, the electric motors operating the pumps L and V areone-quarter horsepower motors. The operating pressure at the lowerpressure side of the system is 25 p.s.i. and the high pressure side is125 p.s.i., creating an operating pressure differential of 100 p.s.1.

In the event the pressure side of the system increases and becomesexcessive, a bypass valve 50 is provided in the flow line 20 ahead ofthe generator G and is connected, as by a line 51, to the line 33downstream from the generator, thereby effectively bypassing thegenerator.

It has been found that the generator G is essential to start or initiateoperation of the system. Under certain operating conditions andparticularly where the temperature of the ambient air is low and thedemand of the evaporator is low, the generator G can, subsequent toputting the system in operation, be cut out or bypassed without adverseeffects.

In accordance with common practice, the system can be provided with adrier 60 and sight glass 61. In the case illustrated, the drier andsight glass are arranged in the liner 41.

In practice, the system can be provided with any suitable control means.In the case illustrated, the system is under control of a master switch70, which switch controls the flow of current to the motors E and E andto the motor of a blower X related to the evaporator.

The motor E is preferably a two-speed motor and Such that it willnormally run at full speed and is such that it can be shunted to operateat half speed, thereby reducing the rate of flow of refrigerant issuingfrom the pump L and flowing through the system, when the system reachesoperating temperature and so the system will not shunt.

The motor E is under control of a two-way pressure responsive switch 72engaged in the line 41 and suitably connected with the master switch 70.

Since the details of the control means can vary widely without departingfrom or effecting the spirit of this invention, we will not burden thisdisclosure with further details of the control means shown or of otheralternative and more complicated control means that have provensatisfactory.

Having described only a typical preferred form and application of ourinvention, we do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to ourselves anymodifications and/or variations that may appear to those skilled in theart.

Having described our invention, we claim:

1. In a refrigeration system, including an evaporator, an accumulatorreceiving refrigerant from the evaporator, refrigerant transportingmeans to remove refrigerant from the accumulator and to discharge it atincreased pressure, a condenser to condense the refrigerant dischargedby the transporting means, a receiver collecting condensed refrigerantfrom the condenser and flow control and expansion means between thereceiver and the evaporator to control the rate of flow of liquidrefrigerant from the receiver and into the evaporator, said accumulatorbeing a liquid vapor phase separator having an inlet connected with theevaporator, a liquid outlet opening and a vapor outlet opening, saidrefrigerant transporting means including a liquid pump connected withthe liquid outlet opening, a vapor pump connected with the vapor outletopening and a generator receiving liquid and vapor refrigerant from thepumps and discharging said refrigerant into the condenser.

2. A structure as set forth in claim 1 wherein a delivery line extendsfrom the liquid pump to the generator and vapor line extends from thevapor pump to said delivery line, said system further including means inthe delivery line between the liquid pump and the vapor line to increasethe rate of flow of liquid refrigerant delivered by the liquid pump andcreate a pressure drop in the delivery line downstream from said means.

3. A structure as set forth in claim 1 wherein a delivery line extendsfrom the liquid pump to the generator and vapor line extends from thevapor pump to said delivery line, said system further including means inthe delivery line between the liquid pump and the vapor line to increasethe rate of flow of liquid refrigerant delivered by the liquid pump andcreate a pressure drop in the delivery line downstream from said means,said means including a flow restriction in the flow line.

4. A structure as set forth in claim 1 wherein a delivery line extendsfrom the liquid pump to the generator and vapor line extends from thevapor pump to said delivery line, said system further including means inthe delivery line between the liquid pump and the vapor line to increasethe rate of flow of liquid refrigerant delivered by the liquid pump andcreate a pressure drop in the delivery line downstream from said means,said means including a venturi in the flow line.

5. A structure as set forth in claim 1 wherein said generator includes aboiler portion with inlet and outlet openings, said inlet openingconnected with the delivery line, said outlet opening connected with aflow line connecfed with the condenser, and a heater portion with inletand outlet portions and into and out of which hot gas from a heat sourceare conducted.

6. A structure as set forth in claim 1 wherein a delivery line extendsfrom the liquid pump to the generator and vapor line extends from thevapor pump to said delivery line, said system further including means inthe delivery line between the liquid pump and the vapor line to increasethe rate of flow of liquid refrigerant delivered by the liquid pump andcreate pressure drop in the delivery line downstream from said means,each of said pumps being driven by an electric motor, the motor drivingthe liquid pump being a two-speed motor and under control of a pressureresponsive switch responsive to refrigerant pressure in the flow controland expansion means whereby the speed and output of the liquid pump isresponsive to the pressures in the system.

7. A structure as set forth in claim 1 wherein a delivery line extendsfrom the liquid pump to the generator and vapor line extends from thevapor pump to said delivery line, said system further including means inthe delivery line between the liquid pump and the vapor line to increasethe rate of flow of liquid refrigerant delivered by the liquid pump andcreate pressure drop in the delivery line downstream from said means,each of said pumps being driven by electric motors, the motor drivingthe liquid pump being a two-speed motor and under control of a pressureresponsive switch responsive to refrigerant pressure in the flow controland expansion means whereby the speed and output of the liquid pump isresponsive to the pressures in the system, said flow control andexpansion means including an expansion valve at the inlet end of theevaporator, a liquid line from the receiver to the expansion valve andflow metering means in the liquid line to control the volume ofrefrigerant flowing through the liquid line.

References Cited UNITED STATES PATENTS 2,032,287 2/1936 Kitzmiller 625032,632,304 3/1953 White. 3,008,303 11/1961 Ruse 62-238 MEYER PERLIN,Primary Examiner

